Biology subjects

Garcia, N. M.

Publications and source records attributed to Garcia, N. M..

6 recordsLinked to original sources

bioRxiv2025

Menin inhibition impairs metastatic colonization of Ewing sarcoma

Menin is a scaffolding protein that interacts with context-specific partners to regulate gene expression. In MLL-rearranged leukemias, Menin:MLL interactions drive leukemogenesis and Menin inhibitors have been FDA approved for these cancers. We previously reported that Menin promotes oncogenic phenotypes in Ewing sarcoma (EwS). Here, we sought to define EwS-specific functions of Menin and determine if Menin inhibitors could be therapeutically leveraged for these tumors. Genetic knockout of Menin had no impact on EwS cell proliferation in vitro but metastatic potential of Menin-depleted cells in vivo was impaired. Transcriptional profiling of Menin knockout cells in vitro showed reproducible downregulation of MYC signature genes and upregulation of developmental programs. Conversely, transcriptional rewiring of developmental genes and restoration of MYC target gene expression were evident in tumors that arose from Menin knockout cells. Exposing EwS cells to the Menin inhibitor VTP50469 (revumenib) inhibited expression of MYC targets and co-immunoprecipitation studies detected Menin:MYC interactions that were partially disrupted by the drug. Metastatic colonization of disseminated EwS cells in vivo was significantly inhibited in mice fed VTP50469 chow. Together these findings implicate Menin as a mediator of EwS metastasis and suggest that Menin inhibitors warrant investigation as novel therapeutics for patients with high-risk disease.

cancer biology↗

bioRxiv2025

Transcriptional Rewiring of BET Inhibitor Treated Ewing Sarcoma Cells Augments their Dependency on Focal Adhesion Kinase

Epigenetic dysregulation is a hallmark of cancer. Small molecule inhibitors such as bromodomain and extraterminal (BET) protein inhibitors developed to target epigenetic dependencies have demonstrated significant promise in preclinical models. However, clinical success with epigenetic drugs as single agents has been limited by emergence of tumor cell tolerance and escape, which often occurs due to transcriptional rewiring. Ewing sarcoma (EwS), a bone and soft tissue tumor driven by the EWS::FLI1 fusion oncoprotein, is characterized by profound oncogene-dependent enhancer reprogramming. Thus, epigenetic modifying therapies are of high therapeutic interest. In this study, we sought to elucidate how EwS cells escape BET inhibition to identify biologically informed drug combinations that could be advanced to clinical trials. As expected, EwS cells and xenografts initially responded to BMS-986158, a pharmaceutical grade BET inhibitor, but proliferation was rapidly restored. A kinase inhibitor screen showed that BMS-986158 drug tolerant persister (DTP) cells were sensitive to inhibitors of Focal Adhesion Kinase (FAK), a critical signaling node downstream of extracellular matrix (ECM) engagement. RNA sequencing revealed that DTP cells had been transcriptionally rewired and that mesenchymal signature and ECM remodeling genes were specifically upregulated. Combining BMS-986158 with the FAK inhibitor Defactinib had synergistic effects, reducing EwS cell proliferation, survival, and invasion in vitro, and significantly inhibited tumor outgrowth in vivo. Our studies identify BET and FAK inhibition as a rational combination therapy worthy of further investigation for EwS, and demonstrate that defining emergent mechanisms of epigenetic drug tolerance can identify new vulnerabilities that can be therapeutically targeted.

cancer biology↗

bioRxiv2025

Zebrafish larval GPR132b differentially influences wound repair and infection control

GPR132 (G2A), a lipid- and pH-sensing GPCR, has been implicated in both pro- and anti-inflammatory signaling, but its in vivo function in wound repair and infection control remains unknown. Here, we investigated the role of GPR132b, a zebrafish homolog of G2A, in regulating innate immune responses. Using CRISPR-Cas9, we generated gpr132b mutants and found that they exhibit enhanced wound healing following sterile injury but increased susceptibility to Listeria monocytogenes infection, indicating that GPR132b modulates a trade-off between wound repair and antimicrobial defense. The enhanced regrowth phenotype was associated with increased macrophage accumulation at the wound site and reduced basal expression of the pro-inflammatory cytokine tnf-. Macrophage depletion suppressed the enhanced regrowth phenotype, suggesting a functional role for macrophages in GPR132b-mediated repair. Pharmacological inhibition of cyclooxygenase (COX) and 12-lipoxygenase (12-LOX) pathways mimicked the gpr132b mutant phenotype in wild-type larvae, indicating that GPR132b likely responds to lipid-derived signals. Together, our findings reveal that GPR132b acts as a context-dependent regulator of innate immunity, impairing efficient tissue repair in sterile conditions while supporting pathogen resistance during infection. Our results underscore the importance of GPCR-mediated signaling in orchestrating effective responses to tissue injury and infection.

immunology↗

bioRxiv2025

Autocrine TGFβ2 enforces a transcriptionally hybrid cell state in Ewing sarcoma

Sub-populations of cancer-associated fibroblast (CAF)-like tumor cells deposit extracellular matrix (ECM) proteins that support Ewing sarcoma (EwS) progression and metastasis. We previously showed a hallmark of CAF-like EwS cells is their hybrid transcriptional state wherein the driver fusion oncogene, EWS::FLI1, maintains activation of proliferative programs but loses capacity to repress mesenchymal genes. Here, we studied primary patient tumors and cell line models to identify molecular drivers of this hybrid state. Our data reveal that hybrid EwS cells are induced and maintained by a TGF{beta} signaling positive feedback loop. Hybrid cells de-repress TGFBR2 and upregulate expression and secretion of TGF{beta}2 to sustain pathway activation and ECM deposition. While TGF{beta} ligands can potently induce growth arrest in cells of epithelial origin, we show that TGF{beta}1 and TGF{beta}2 promote cell invasion of EwS cells without affecting proliferation. Thus, stroma and tumor-derived TGF{beta} ligands induce and maintain hybrid EwS cells to promote pro-metastatic cell phenotypes.

cancer biology↗

bioRxiv2025

Determining preclinical safety of Aclarubicin in pediatric malignancies

BackgroundAnthracyclines are among the most effective chemotherapeutic agents used to treat pediatric malignancies. However, their clinical use is limited by dose-dependent toxicities, particularly cardiotoxicity and secondary malignancies. Aclarubicin (Acla) is an anthracycline derivative that induces chromatin damage while sparing DNA, offering potential therapeutic benefit with reduced longterm toxicity. MethodsWe evaluated the anti-tumor efficacy and safety profile of Acla in multiple in vitro pediatric cancer models and in vivo mouse models designed to mimic anthracycline re-treatment following prior doxorubicin (Doxo) exposure. Tumor growth, genotoxic stress, survival, and organ toxicity were assessed. ResultsAcla demonstrated robust anti-tumor activity comparable to Doxo across diverse pediatric in vitro models. Unlike Doxo, Acla treatment did not induce significant genotoxic stress. In vivo, mice receiving Acla after Doxo exposure showed no evidence of cumulative cardiotoxicity or end-organ damage. In contrast, a second course of Doxo led to significant toxic mortality, but was surprisingly not attributable to classic cardiac injury. ConclusionOur study highlights Acla as a promising anthracycline derivative for pediatric cancers, with potent anti-tumor efficacy and a superior safety profile, even following prior anthracycline exposure. These results support continued investigation of chromatin-damaging anthracyclines that can kill pediatric cancer cells without inducing genotoxic stress. In addition, our studies underscore the need to refine preclinical models to better understand both acute and chronic anthracycline toxicities in pediatric and adolescent populations.

cancer biology↗

bioRxiv2023

Carcinoma-associated fibroblast-like tumor cells remodel the Ewing sarcoma tumor microenvironment

Tumor heterogeneity is a major driver of cancer progression. In epithelial-derived malignancies, carcinoma-associated fibroblasts (CAFs) contribute to tumor heterogeneity by depositing extracellular matrix (ECM) proteins that dynamically remodel the tumor microenvironment (TME). Ewing sarcomas (EwS) are histologically monomorphous, mesenchyme-derived tumors that are devoid of CAFs. Here we identify a previously uncharacterized subpopulation of transcriptionally distinct EwS tumor cells that deposit pro-tumorigenic ECM. Single cell analyses revealed that these CAF-like cells differ from bulk EwS cells by their upregulation of a matrisome-rich gene signature that is normally repressed by EWS::FLI1, the oncogenic fusion transcription factor that underlies EwS pathogenesis. Further, our studies showed that ECM-depositing tumor cells express the cell surface marker CD73, allowing for their isolation ex vivo and detection in situ. Spatial profiling of tumor xenografts and patient biopsies demonstrated that CD73+ EwS cells and tumor cell-derived ECM are prevalent along tumor borders and invasive fronts. Importantly, despite loss of EWS::FLI1-mediated gene repression, CD73+ EwS cells retain expression of EWS::FLI1 and the fusion-activated gene signature, as well as tumorigenic and proliferative capacities. Thus, EwS tumor cells can be reprogrammed to adopt CAF-like properties and these transcriptionally and phenotypically distinct cell subpopulations contribute to tumor heterogeneity by remodeling the TME.

cancer biology↗